So if new kitty is feral, you'll release her back into her home area.

But if kitty is a stray, could you home two cats in your super cage on the balcony (i.e. When you catch up with Gracie) Or will this one go to a nice no kill shelter to be rehomed ?

I just have visions of these cats, being inside cats no 6 & 7 !!

Best of luck with both cats. May you catch Gracie soon and you did a great thing paying for new cats altering etc.